SMHIs rapportserie: RMK (Meteorologi och klimatologi)http://www.smhi.se/cm/smhis-rapportserie-rmk-meteorologi-och-klimatologi-1.18360
De senaste rapporterna i SMHIs rapportserie RMK. Raporterna i serien är huvudsakligen skrivna på engelska för en internationell publik.CORDEX scenarios for Europe from the Rossby Centre regional climate model RCA4https://www.smhi.se/publikationer/publikationer/cordex-scenarios-for-europe-from-the-rossby-centre-regional-climate-model-rca4-1.90272
Denna rapport dokumenterar klimatmodellsimuleringar på 50 km horisontell upplösning över Europa med Rossby Centres regionala atmosfärsmodell (RCA4) gjorda inom projektet Coordinated Regional Downscaling Experiment (CORDEX) för i) ERAInterim-drivna (ERAINT) simuleringar för att utvärdera förmågan hos RCA4 att simuleraden senaste tidens klimat, ii) historiska simuleringar av de senaste årtiondena med drivning från nio olika globala klimatmodeller (GCM:er) och iii) framtidsscenarierna RCP 4,5 och RCP 8,5 drivna med samma GCM:er. Dessa simuleringar representerar en delmängd av alla CORDEX-simuleringar producerade vid Rossby Centre och en allmän slutsats dragen vid Rossby Centre är att en sådan ensemble inte varit möjlig utan att först etablera den effektiva produktionskedja som beskrivs här.Första delen av rapporten dokumenterar RCA4 och dess förmåga i en simulering där ERAINT skalades ner. RCA4 återskapar till stor del den storskaliga cirkulationen från ERAINT, men några lokala avvikelser förekommer. I allmänhet simuleras säsongscykler för temperatur och nederbörd i överensstämmelse med observationer. Några avvikelser finns, som för mycket nederbörd i norra Europa och för lite i södra. På vintern är det även för mycket nederbörd i östra Europa. Temperaturen är i allmänhet underskattad i norra Europa och i medelhavsområdet på vintern, medan för höga temperaturer ges i sydöstra Europa på vintern och i medelhavsområdet på sommaren.RCA4 presterar i allmänhet bra i simuleringar av den senaste tidens klimat med randvillkor från GCM:er. En stor del av det simulerade klimatet i RCA4 kan tillskrivas den drivande GCM:en, men RCA4 skapar sitt eget klimat inuti modelldomänen och lägger till detaljer på grund av högre upplösning. Alla nio nedskalade GCM:er har gemensamma problem i representationen av den storskaliga cirkulationen på vintern. Denna egenskap förs vidare till RCA4. Avvikelserna i storskalig cirkulation medför avvikelser i temperatur och nederbörd i RCA4.Klimatförändringssignalen som den simuleras av RCA4-ensembler enligt RCP 4,5 och RCP 8,5 är mycket lika tidigare resultat. I både scenario RCP 4,5 och RCP 8,5 beräknas Europa bli varmare i framtiden. På vintern är uppvärmningen störst i norra Europa, och på sommaren i södra Europa. Den högsta dygnsmedeltemperaturen på sommaren ökar på ungefär samma sätt som sommartemperaturen, men något mer i södra Europa. Den lägsta<br />
dygnsmedeltemperaturen på vintern i norra Europa är den temperatur som förändras mest. Nederbörden beräknas öka under alla årstider i norra Europa och minska i södra Europa. Den största dygnsnederbörden (och per sjudagarsperiod) beräknas öka i nästan hela Europa och i alla årstider. Samtidigt beräknas den längsta perioden utan nederbörd att bli längre i södra Europa. I allmänhet förutses små förändringar i medelvindhastighet. Det finns emellertid områden med signifikanta förändringar i vind.Att använda ensembler är ett sätt att beskriva osäkerheterna i scenarierna, men det finns andra möjliga ensembler som använder andra modeller och som skulle ge andra resultat. Ändå anses den ensemble som används här vara tillräckligt lik dessa andra ensembler för att vara representativ för den hela mängden GCM:er. Dynamisk nedskalning med RCA4 förändrar klimatförändringssignalen, och spridningen i ensemblen minskar ibland, men<br />
ensemblen med nio RCA4 simuleringar med olika GCM:er anses vara representativ för den hela ensemblen. Alla scenarier är överens om mönstret på klimatförändringen, men storleken på förändringen bestäms av valet av scenario. Den relativa betydelsen av valet av scenario ökar med tiden.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 116</div><div><strong>Författare: </strong>Gustav Strandberg, Lars Bärring, Ulf Hansson, Christer Jansson, Colin Jones, Erik
Kjellström, Michael Kolax, Marco Kupiainen, Grigory Nikulin, Patrick Samuelsson,
Anders Ullerstig and Shiyu Wang</div><div><strong>Publicerad: </strong>juni 2015</div>Tue, 16 Jun 2015 07:19:15 GMThttps://www.smhi.se/publikationer/publikationer/cordex-scenarios-for-europe-from-the-rossby-centre-regional-climate-model-rca4-1.902722015-06-16T07:19:15Zhttp://viaf.org/viaf/153618105gratistext/htmlTemperature and precipitation changes in Sweden; a wide range of model-based projections for the 21st century.https://www.smhi.se/publikationer/temperature-and-precipitation-changes-in-sweden-a-wide-range-of-model-based-projections-for-the-21st-century-1.6648
In this report we analyze the climate change signal for Sweden in scenarios for the 21st century in a large number of coupled atmosphere-ocean general circulation models (AOGCMs), used in the fourth assessment report by the Intergovernmental Panel on Climate Change (IPCC). We focus on near-surface temperature and precipitation. The analysis includes six emission scenarios as well as multi-member runs with the AOGCMs. At the Rossby Centre, SMHI, regional climate models have been run under different emission scenarios and driven by a few AOGCMs. The results of those runs have been used as a basis in climate change, impact and adaptation assessments. Here, we evaluate results from these regional climate model runs in relation to the climate change signal of the IPCC AOGCMs. First, simulated conditions for the recent past (1961-1990) are evaluated. Generally, most AOGCMs tend to have a cold bias for Sweden, especially in winter that can be as large as 10°C. Also, the coarse resolution of the AOGCMs leads to biases in simulated precipitation, both in averages, extremes and often also in the phase of the seasonal cycle. Generally, AOGCMs overestimate precipitation in winter; biases reach 30-40% or even more. In summer, some AOGCMs overestimate precipitation while others underestimate it. Projected responses depend on season and geographical region. Largest signals are seen in winter and in northern Sweden, where the mean simulated temperature increase among the AOGCMs (and across the emissions scenarios B1, A1B and A2) is nearly 6°C by the end of the century, and precipitation increases by around 25%. In southern Sweden, corresponding values are around +4°C and +11%. In summer, the temperature increase is more moderate, which is also the case for precipitation. The regional climate signals are usually within the ranges given by the AOGCM runs, however, the regional models tends to show larger increases in winter, and smaller increases in summertime precipitation.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 113</div><div><strong>Författare: </strong>Petter Lind, Erik Kjellström </div><div><strong>Publicerad: </strong>december 2008</div>Mon, 01 Dec 2008 00:00:00 GMThttps://www.smhi.se/publikationer/temperature-and-precipitation-changes-in-sweden-a-wide-range-of-model-based-projections-for-the-21st-century-1.66482008-12-01T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/htmlClimate indices for vulnerability assessmentshttps://www.smhi.se/publikationer/climate-indices-for-vulnerability-assessments-1.2097
The demand is growing for practical information on climate projections and the impacts expected in different geographical regions and different sectors. It is a challenge to transform the vast amount of data produced in climate models into relevant information for climate change impact studies. Climate indices based on climate model data can be used as means to communicate climate change impact relations. In this report a vast amount of results is presented from a multitude of indices based on different regional climate scenarios.
The regional climate scenarios described in this report show many similarities with previous scenarios in terms of general evolution and amplitude of future European climate change. The broad features are manifested in increases in warm and decreases in cold indices. Likewise are presented increases in wet indices in the north and dry indices in the south.
Despite the extensive nature of the material presented, it does not cover the full range of possible climate change. We foresee a continued interactive process with stakeholders as well as continued efforts and updates of the results presented in the report.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 111</div><div><strong>Författare: </strong>Gunn Persson, Lars Bärring, Erik Kjellström, Gustav Strandberg, Markku Rummukainen</div><div><strong>Publicerad: </strong>augusti 2007</div>Sat, 04 Aug 2007 00:00:00 GMThttps://www.smhi.se/publikationer/climate-indices-for-vulnerability-assessments-1.20972007-08-04T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/htmlClimate change scenario simulations of wind, sea level, and river discharge in the Baltic Sea and Lake Mälaren region – a dynamical downscaling approach from global to local scaleshttps://www.smhi.se/publikationer/climate-change-scenario-simulations-of-wind-sea-level-and-river-discharge-in-the-baltic-sea-and-lake-malaren-region-a-dynamical-downscaling-approach-from-global-to-local-scales-1.2101
A regional climate model (RCM) and oceanographic, hydrological and digital elevation models were applied to study the impact of climate change on surface wind, sea level, river discharge, and flood prone areas in the Baltic Sea region. The RCM was driven by two global models and two emission scenarios. According to the four investigated regional scenario simulations, wind speed in winter is projected to increase between 3 and 19% as an area average over the Baltic Sea. Although extremes of the wind speed will increase about as much as the mean wind speed, sea level extremes will increase more than the mean sea level, especially along the eastern Baltic coasts. In these areas projected storm events and global average sea level rise may cause an increased risk for flooding. However, the Swedish east coast will be less affected because mainly the west wind component in winter would increase and because land uplift would compensate for increased sea levels, at least in the northern parts of the Baltic. One of the aims of the downscaling approach was to investigate the future risk of flooding in the Lake Mälaren region including Stockholm city. In Stockholm the 100-year surge is projected to change between -51 and 53 cm relative to present mean sea level suggesting that in the city the risk of flooding from the Baltic Sea is relatively small because the critical height of the jetty walls will not be exceeded. Lake Mälaren lies just to the west of Stockholm and flows directly into the Baltic Sea to the east. This study addresses also the question of how the water level in Lake Mälaren may be affected by climate change by incorporating the following three contributing components into an analysis: 1) projected changes to hydrological inflows to Lake Mälaren, 2) changes to downstream water levels in the Baltic Sea, and 3) changes in outflow regulation from the lake. The first component is analyzed using hydrological modeling. The second and third components employ the use of a lake discharge model. An important conclusion is that projected changes to hydrological inflows show a stronger impact on lake levels than projected changes in water level for the Baltic Sea. Furthermore, an identified need for increased outflow capacity from the lake for the present climate does not diminish with projections of future climate change. The tools developed in this work provide valuable inputs to planning for both present and future operations of water level in Lake Mälaren. Based on the oceanographic and hydrological scenario simulations, flood prone areas were analysed in detail for two municipalities, namely Ekerö and Stockholm. The GIS analysis of both municipalities indicates a series of affected areas. However, in case of the 100-year flood (0.65 m above the mean lake level) in present climate or even in case of the maximum probable flood (1.48 m above the mean lake level) the potential risks will be relatively low.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 109</div><div><strong>Författare: </strong>Meier, H.E.M., J. Andréasson, B. Broman, L.P. Graham, E. Kjellström, G. Persson, M.
Viehhauser</div><div><strong>Publicerad: </strong>februari 2006</div>Sun, 05 Feb 2006 00:00:00 GMThttps://www.smhi.se/publikationer/climate-change-scenario-simulations-of-wind-sea-level-and-river-discharge-in-the-baltic-sea-and-lake-malaren-region-a-dynamical-downscaling-approach-from-global-to-local-scales-1.21012006-02-05T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/htmlA 140-year simulation of European climate with the new version of the Rossby Centre regional atmospheric climate model (RCA3).https://www.smhi.se/publikationer/a-140-year-simulation-of-european-climate-with-the-new-version-of-the-rossby-centre-regional-atmospheric-climate-model-rca3-1.2107
This report presents the latest version of the Rossby Centre regional atmospheric model, RCA3, with focus on model improvements since the earlier version, RCA2. The main changes in RCA3 relate to the treatment of land surface processes. Apart from the changes in land surface parameterizations several changes in the calculation of radiation, clouds, condensate and precipitation have been made. The new parameterizations hold a more realistic description of the climate system.
Simulated present day climate is evaluated compared to observations. The new model version show equally good, or better, correspondence to observational climatologies as RCA2, when forced by perfect boundary conditions. Seasonal mean temperature errors are generally within ±1oC except during winter in north-western Russia where a larger positive bias is identified. Both the diurnal temperature range and the annual temperature range are found to be underestimated in the model. Precipitation biases are generally smaller than in the corresponding reanalysis data used as boundary conditions, showing the benefit of a higher horizontal resolution.
The model is used for the regionalization of two transient global climate change projections for the time period 1961- 2100. The radiative forcing of the climate system is based on observed concentrations of greenhouse gases until 1990 and on the IPCC SRES B2 and A2 emissions scenarios for the remaining time period. Long-term averages as well as measures of the variability around these averages are presented for a number of variables including precipitation and near-surface temperature. It is shown that the changes in variability sometimes differ from the changes in averages. For instance, in north-eastern Europe, the mean increase in wintertime temperatures is followed by an even stronger reduction in the number of very cold days in winter. This kind of performance of the climate system implies that methods of inferring data from climate change projections to other periods than those actually simulated have to be used with care, at least when it comes to variables that are expected to change in a non-linear way. Further, these new regional climate change projections address the whole 21st century.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 108</div><div><strong>Författare: </strong>Erik Kjellström, Lars Bärring, Stefan Gollvik, Ulf Hansson, Colin Jones, Patrick Samuelsson,
Markku Rummukainen, Anders Ullerstig, Ulrika Willén, Klaus Wyser</div><div><strong>Publicerad: </strong>december 2005</div>Mon, 05 Dec 2005 00:00:00 GMThttps://www.smhi.se/publikationer/a-140-year-simulation-of-european-climate-with-the-new-version-of-the-rossby-centre-regional-atmospheric-climate-model-rca3-1.21072005-12-05T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/htmlThe Meteorological Auto Code (MAC) and Numerical Weather Prediction (NWP) at SMHIhttps://www.smhi.se/publikationer/publikationer/the-meteorological-auto-code-mac-and-numerical-weather-prediction-nwp-at-smhi-1.102779
Sverige var ett föregångsland inom numeriska väderprognoser och den allra första operativa väderprognosen gjordes redan 1954 på det Internationella Meteorologiska Institutet i Stockholm. SMHI kom igång senare, men 1961 startade man ett långsiktigt program för NWP (numerical weather prediction). Projektet växte gradvis under 1960-talet och blev så småningom en central komponent i SMHIs prognostjänst. En utmaning under de tidiga åren var de begränsade dataresurserna med primitiv programvara, och med dagens mått begränsat minnesutrymme och låg beräkningshastighet. För att kompensera dessa brister krävdes både beslutsamhet och ett stort mått av kreativitet. Som en central komponent i arbetet utvecklade NWP-gruppen datorsystemet MAC (Meteorological Auto Code) som här beskrivs i detalj samt också alla de beräkningsprogram som krävdes för prognostjänsten. Detta inkluderade olika prognosmodeller, analys samt program för databehandling och observationskontroll samt produktion av prognosresultaten i grafisk eller digital form.<br /> <br /> Det är vår förhoppning att föreliggande artikel skall ge den yngre generationen en inblick i hur det var att syssla med NWP under 1960-talet.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 117</div><div><strong>Författare: </strong>Lennart Bengtsson, Nils Gustafsson1), Bo Döös2), Daniel Söderman, Lars Moen3),
Thomas Thompson4), Paul Jakobsson, Gunnar Bleckert, Ann-Beate Henriksson, Bo
Lindgren5) and Per Kållberg
1)Correspondig author, e-mail: Nils.Gustafsson@smhi.se
2)Deceased 2010
3)Deceased 2006
4)Deceased 2015
5)Deceased 2005</div><div><strong>Publicerad: </strong>april 2016</div>Fri, 01 Apr 2016 08:10:00 GMThttps://www.smhi.se/publikationer/publikationer/the-meteorological-auto-code-mac-and-numerical-weather-prediction-nwp-at-smhi-1.1027792016-04-01T08:10:00Zhttp://viaf.org/viaf/153618105gratistext/htmlMATCH-SALSA Multi-scale Atmospheric Transport and CHemistry model coupled to the SALSA aerosol microphysics modelhttps://www.smhi.se/publikationer/match-salsa-multi-scale-atmospheric-transport-and-chemistry-model-coupled-to-the-salsa-aerosol-microphysics-model-1.34623
This report presents a new aerosol dynamics version of a European scale Eulerian CTM, MATCH. The new model is called MATCH-SALSA, and includes aerosol microphysics and several options for nucleation, wet scavenging and condensation. The report entails model description, evaluation and sensitivity tests.
The new model reproduces observed higher particle number concentration (PNC) in central Europe and lower in remote regions. The model peak PNC occurs at the same particle size as the observed peak or at smaller sizes, which indicate missing growth. Total PNC is underestimated at some sites. The model performs well for particle mass, including SIA components. EC and OC are underestimated at many of the sites.
The results are sensitive to the fraction of SOx emitted as H2SO4 and the optimum choice is site dependent. The model results are highly sensitive to whether organic nucleation is included or not. The model results are sensitive to amount of organic vapors in the condensation.
The model can be used in applications knowing the restrictions of what the model manages well and what needs further improvements, which is detailed in the report.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 115</div><div><strong>Författare: </strong>Camilla Andersson, Robert Bergström, Cecilia Bennet, Manu Thomas, Lennart Robertson, SMHI.
Harri Kokkola, Hannele Korhonen and Kari Lehtinen. FMI.</div><div><strong>Publicerad: </strong>december 2013</div>Wed, 04 Dec 2013 00:00:00 GMThttps://www.smhi.se/publikationer/match-salsa-multi-scale-atmospheric-transport-and-chemistry-model-coupled-to-the-salsa-aerosol-microphysics-model-1.346232013-12-04T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/htmlNordic regionalisation of a greenhouse-gas stabilisation scenariohttps://www.smhi.se/publikationer/nordic-regionalisation-of-a-greenhouse-gas-stabilisation-scenario-1.2099
The impact of a CO2 stabilisation on the Swedish climate is investigated with the regional climate model RCA3 driven by boundary conditions obtained from a global coupled climate system model (CCSM3). The global model has been forced with observed greenhouse gas concentrations from pre-industrial conditions until today’s, and with an idealised further increase until the stabilisation level is reached. After stabilisation the model integration continues for another 150+ years in order to follow the delayed response of the climate system over a period of time.
Results from the global and regional climate model are compared against observations and ECMWF reanalysis for 1961-1990. For this period, the global model is found to be too cold over Europe and with a zonal flow from the North Atlantic towards Europe that is too strong. The climate of the driving global model controls the climate of the regional model and the same deviations from one are thus inherited by the other. We therefore analyse the relative climate changes differences, or ratios, of climate variables between future's and today's climate.
Compared to pre-industrial conditions, the global mean temperature changes by about 1.5oC as a result of the stabilisation at 450 ppmv equivalent CO2. Averaged over Europe, the temperature change is slightly larger, and it is even larger for Sweden and Northern Europe. Annual mean precipitation for Europe is unaffected, but Sweden receives more precipitation under higher CO2 levels. The inter-annual and decadal variability of annual mean temperature and precipitation does not change with any significant degree.
The changes in temperature and precipitation are not evenly distributed with the season: the largest warming and increased precipitation in Northern Europe occurs during winter months while the summer climate remains more or less unchanged. The opposite is true for the Mediterranean region where the precipitation decreases mostly during summer. This also implies higher summer temperatures, but changes in winter are smaller. No substantial change in the wind climate over Europe is found.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 110</div><div><strong>Författare: </strong>Klaus Wyser, Markku Rummukainen, Gustav Strandberg</div><div><strong>Publicerad: </strong>oktober 2006</div>Wed, 04 Oct 2006 00:00:00 GMThttps://www.smhi.se/publikationer/nordic-regionalisation-of-a-greenhouse-gas-stabilisation-scenario-1.20992006-10-04T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/html2D meso-scale re-analysis of precipitation, temperature and wind over Europe - ERAMESANhttps://www.smhi.se/publikationer/2d-meso-scale-re-analysis-of-precipitation-temperature-and-wind-over-europe-eramesan-1.2092
The need for long time series of gridded meteorological data with a fine spatial and temporal resolution has increased in recent years. The requirements for this type of gridded meteorological data fields arise from many different areas of the society, in connection to atmospheric environment studies of air quality and deposition and trends in these parameters, regional climate change, wind energy, hydrological studies etc. The aim of the present project is to investigate the possibility of producing historical, high quality and time consistent, meso-scale re analyses for the whole of Europe regarding precipitation, 2 m temperature and wind for at least 25 years back in time.
The MESAN analysis system (Häggmark et al., 2000) at SMHI was chosen as a basis for the reanalysis and the system was adjusted to cover the whole of Europe. In order to find the most appropriate first guess fields to be used in the MESAN system, a pilot study was performed. ERA- 40 data from ECMWF was selected as best possible first guess fields for the re analysis. The performed re-analysis, which is denoted ERAMESAN, includes gridded data covering all Europe with a time resolution of 6 h and a spatial resolution of 0.1º (11 km) in a rotated latitude longitude coordinate system for the time-period 1980-2004. All analyses are archived in GRIB-format and stored on disc at SMHI. The dataset is also available within the EUMETNET optional programme Showcase EUROGRID.
A partial validation for the years 1998-2000, using a cross validation procedure with independent observations (5.5% of the total amount of stations), shows an improvement in ERAMESAN compared to the ERA-40 data for all studied parameters with regard to root mean square deviation, mean absolute deviation and mean bias deviation for all seasons. The deviations are roughly of the order of 15% smaller compared to what is obtained from ERA-40. The frequency distribution of large precipitation amounts per day and high wind speeds are substantially better described in ERAMESAN compared to ERA-40. However, the tendency to underestimate the frequency of very large precipitation amounts or high wind speeds, compared to observations, can be seen also for ERAMESAN. It is important to be aware of this limitation when using ERAMESAN data for practical applications concerning evaluation of risks for extreme wind speeds or very large precipitation amounts or in e.g. wind energy studies.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 112</div><div><strong>Författare: </strong>Anna Jansson, Christer Persson, Gustav Strandberg</div><div><strong>Publicerad: </strong>december 2007</div>Tue, 04 Dec 2007 00:00:00 GMThttps://www.smhi.se/publikationer/2d-meso-scale-re-analysis-of-precipitation-temperature-and-wind-over-europe-eramesan-1.20922007-12-04T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/htmlAssessing and improving the Swedish forecast and information capabilities for ground-level ozonehttps://www.smhi.se/publikationer/assessing-and-improving-the-swedish-forecast-and-information-capabilities-for-ground-level-ozone-1.17910
This study aims to assess and improve the Swedish forecast and information capabilities for ground-level ozone concentrations in ambient air. The assessment is based on a set of archived results from the Swedish operational chemical transport model MATCH and Swedish in-situ measurements of ozone covering the period of May 2008 to November 2010. The evaluation comprises two major activities: The first activity is an analysis of the overall model performance using standard statistical metrics suitable for longer time series. The second evaluation activity comprises in-detail analyses of the specific ozone episodes occurring in Sweden during the study period. In addition, trajectory modelling is used to investigate the meteorological conditions and transport patterns associated with those episodes. The evaluation of the model results shows that the model scores well according to standard evaluation criteria and confirms results of other studies in that the model easily meets the data quality requirements of the EU air quality directive 2008/50/EC. However, from an operational forecasting and information perspective it would be desirable to further improve the prediction of, in particular, high-level ozone episodes. Two different activities in our study are dedicated to the task of improving the forecast and information capabilities: The first activity tests the usefulness of statistical postprocessing of model results using regression techniques. The tests show promising results although the model performance during high-level ozone episodes is not improved. A limitation of our study is the relatively small archive of model data available for calibration and
evaluation. Adaptive post-processing methods have not been tested in our study. The second activity aimed to improve ozone forecasting is a high-resolution model run for the year 2010. The higher reso-lution run gives slightly better results than the coarser operational model, which can be attributed to a better resolution of the physiography and thus certain physical and chemical processes. In particular, high-resolution simulations provide a more realistic
representation of the spatial ozone variation which is desirable for environmental assessments with a longer time horizon. However, from the perspective of operational ozone forecasting the increase in resolution cannot correct systematic problems such as an under-prediction of ozone if the source of ozone is non-local and the long-range transboundary transport is not correctly described by the European-scale model used as boundaries. Other potential sources of error are incomplete or erroneous emissions, representativeness issues, oversimplifications in the model’s physical or chemical processes, lacking data assimilation and initialization and oversimplified
boundary conditions. While several of these issues are already addressed in current initiatives such as the EU FP7-project MACC, it is clear that further work will be needed during the coming years. Further work should also be invested in a better exploitation of the international developments within MACC and in the establishment of operational high-resolution air quality forecasts for Sweden, using boundary values from European-scale forecasts provided by the
MACC-ensemble of regional air quality models.<div class="smallverticalspace">&nbsp;</div><div><strong>Typ: </strong>Rapport</div><div><strong>Rapportserie: </strong>RMK 114</div><div><strong>Författare: </strong>Thomas Klein, Per-Erik Karlsson, Stefan Andersson, Magnuz Engardt, Karin Sjöberg</div><div><strong>Publicerad: </strong>21 september 2011</div>Wed, 21 Sep 2011 00:00:00 GMThttps://www.smhi.se/publikationer/assessing-and-improving-the-swedish-forecast-and-information-capabilities-for-ground-level-ozone-1.179102011-09-21T00:00:00Zhttp://viaf.org/viaf/153618105gratistext/html